Self-locking lamp-socket.



W. A. STACEY.

SELF LOGKING LAMP SOCKET.

APPLIOATION FILED MAY 16. 1912.

1,054,946. Patented Mar; 4, 1913.

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" fl m M5? UNITED srATEs PATENT OFFICE.

WILLIAM .A. STACEY, OF CHICAGO, ILLINOIS.

SELF-LOCKING LAMP-SOCKET.

Specification of Letters Patent. Application filed May 16, 1912. Serial-NO. 697,703.

Patented Mar. 4, 1913.

To all whom it may concern:

Be it known thatI, WILLIAM A. Smear, a citizen of the United States,residing at Chicago, county of Cook, State of Illinois,

.have invented a certain new and-useful Improvement in Self-LockingLamp-Sockets, and declare the following to be a full, clear, and exactdescription of the same, such as will enable others skilled in the artto which it pertains to make and use the same, ref erence being had tothe accompanyin drawings, which form a part of the speci cation.

My invention relates to lamp sockets and I has for its object to producea simple and tion of the casing being broken away at the base ofthelamp;-Fig. 2 isaside view on a somewhat larger scale of the socketitself with the lamp removed, the casing being omitted; Fig. 3- is-aview similar to Fig. 2, showin a lamp screwed into the socket; Fig. 4 1sa section' through the lamp-receiving end of the socket, with thecasingin positiomand Fig. 5 is a. section on an enarged scale approximately online of" viduality which it may be desired to give to Fig. 4.

Referrin to the drawing, 1 represents the insulating lock or base of alamp socket,

this member having any usual or suitable construction. Connected withthe member 1 i is a coiled spring 2 which forms the receiving member forthe screw-threaded base. of a lamp. The spring is made of wire smallenough to lie within the valleys of a thread on a lamp base the diameterof the wire being less than the pitch'of the thread. The spring. 2 is soformed that normally its coils tend to lie close together, making itnecessary to place the spring under tension in order to separate thecoils.- The result of this construction, assuming that one end of thespringis fastenedto the member 1 and the other. end is: left free,- isthat when a lamp is screwed into the socket, the' coils of the springare spread so as to cause them to follow the threads on the lamp and thetension of the spring causes the coils to take a firm grip on thethreads on the lamp. Consequently, when it is attempted to unscrew thelamp, the friction between the threads and the coils of the spring issuflicient to lock the two together so that a turning movement of thelamp causesthe coils of the springto become wrapped more tightly aboutthe base of the lamp. Consequently, the lamp cannot again be unscrewedunless some means is; provided for holding the spring so that Itseffective diameter cannot be decreased. I have provided means wherebythespring may be held against a wrapping movement around the base of thelamp when some one having a proper key or the like desires to remove thelamp. For this purpose I have turned up thefree end 3 of the spring sothat it lies outside of the spring and transverse to its coils and havearranged-on the usual casing or housing 4.- a suitable adjustable stopwhich may be moved in in front of the upturned end so as to preventmotion thereof in the direction to cause the spring to wrap itself uponthe base of the lamp when the lamp is unscrewed. In the arrangementshown, I have arranged on one side of the member 4.- a projecting sleeveor nipple 5 in which is fitted an insulating bushing 6 having at thecenter a metal sleeve 7 screw threaded interiorly. Screw-threaded intothe sleeve 7 is a post or stud 8 having its outer end 9 shaped toreceive a suitable key; the shape of the member 9 depending upon thedegree of indithe key necessary to turn the post or'stud. The parts areso arranged thatin the normal position of rest of the spring,-that'is, 1

a position when there is no lamp in the socket,the upturned end 3 liesjust at the side of the inner end of the post or stud so that when thepost or stud isscrew ed in it forms a stop against which the upturnedend will strike when the free end of the spring is carried in thedirection to decrease the effective internal diameter of thespring,-that is, in the direction in which the free end of the spring iscarried when the socket. I

The operation is as follows: Normally the post or stud is screwed outfar enough to permit the free end of the spring to move it is attemptedto unscrew a lamp fromi manner.

.struction in which a spring-like past the inner end of the post orstud. Then when a lamp is screwed into the socket, the coils of thespring take a tight grip thereon and, if it is attempted to'unscrew thelamp, the free end of the spring is carried around past the inner end ofthe post or studand the spring is wrapped tightly upon the base. of thelamp; in other words, the lamp is automatically locked to the socket bythe mere act of screwing it into the socket. It

will thus be seen that it is possible'for anyone to screw a lamp into asocket, because no key or other tool is required for first placing thesocket in the proper condition; but it some unauthorized person attemptsto remove the lamp he Wlll find that it is securelylocked in place. Inorder to remove a lamp, some one having a proper key must screw the studor post inwardly so as to make"it efiective as a stop for the free endof the spring, whereupon the lamp may be unscrewed as from any othersocket. the lamp has been removed, the stud or post is screwed back toits original position and the socket is ready to receive another lampand lock it in place. In order to make it more difficult to tamper withthe socket so as to permitan unauthorized person to remove a. lamp, Iprefer to make the screwthreads 10 between the sleeve 7 and the post 8left handed so that the post must be turned in the opposite directionfrom that in which one would naturally turn it to screw it in.

The stationary end of the spring may be fixed to the insulating base inany suitable A very satisfactory arrangement, and one which requiresexisting devices, consists in providing the base 1 with a shortscrew-threaded shell 11,-this bein in fact a piece of the usualscrew;threade socket or a similar piece;- screwing the inner end of thespring into the member 11 and then soldering it thereto. Thisarrangement permits standard terminals to be used and at the same timealines the spring and holds it firmly in place.

While I have illustrated the normal idle condition of the spring as thatin which the coils touch each other, I do not desire to be limited tothis particular arrangement because my invention contemplates anyconcoil is caused to take enough of a hold upon a member screwed into itto cause the coil to -wrap itself upon the member when it is atthelatter. Further- I have illustrated only one specific for efiecting therelease of a lamp,

tempted to unscrew more, means but I do not desire to be limited to theparticular structural details so illustrated. In

After but little change in otherwords, while I have illustrated anddescribed in detail a single preferred embodiment of my invention, I donot desire to be limited to the specific details so illustrated anddescribed; but intend to cover all forms and arrangements which comewithin the terms of the definitions of my invention constituting theappended claims.

I claim:

1. In a device of the character described, a supporting base, a helicalcoil secured at one end to said member and having its other end free,and a movable stop adapted to engage with said free end.

2. In a a support, a helix secured at one end to said support andcomprising one or more turns adapted to engage in the valleys of athread on a lamp, and adjustable holding means for the other end of thehelix.

. 3. In a device of the character described,

device of the character described, 1

support and comprising one or more turns adapted to engage in thevalleys of a thread on a lamp, and a movable holding device arranged tobe moved into the free end of the helix.

4. In a device of the character described, a support,a helix secured atone end to said support and comprising a plurality of turns adapted tolie within the valleys of a thread on a lamp, the normal pitch of thehelix being less than the pitch of said thread, the free end of thehelix side and transverse to the coils, justable stop arranged to bemoved into the path of said free end.

5. In a. device of the character described, asupport, a helix secured atone end to said support and comprising a plurality of turns adapted tolie within the valleys of a thread on a lamp, the normal pitch of thehelix be ing less than the pitch of said thread, the free end of thehelix being bent laterally beside andtransverse to the coils, a casingextending around the helix, and an adjustable stop carried by the casingin position to engage with said free end.

6. In a device of the character described, a support including a shortscrew-threaded sleeve, a helix having one or more of its turns fittingintothe threads in said sleeve at one end and having a tree portioncomprising one or more turns projecting beyond the sleeve.

In testimony whereof, I sign this specification in the presence of twowitnesses.

WILLIAM A. STACEY.

Witnesses:

WM. F. FREUDENREIGH, RUBY V. Burners...

engagement with being bent laterally beand an ad-

